DESCRIPTION

BN_bn2bin() converts the absolute value of a into big-endian form and stores it at to. to must point to BN_num_bytes(a) bytes of memory.

BN_bin2bn() converts the positive integer in big-endian form of length len at s into a BIGNUM and places it in ret. If ret is NULL , a new BIGNUM is created.

BN_bn2hex() and BN_bn2dec() return printable strings containing the hexadecimal and decimal encoding of a respectively. For negative numbers, the string is prefaced with a leading ’−’. The string must be freed later using OPENSSL_free().

BN_hex2bn() converts the string str containing a hexadecimal number to a BIGNUM and stores it in **bn. If *bn is NULL , a new BIGNUM is created. If bn is NULL , it only computes the number’s length in hexadecimal digits. If the string starts with ’−’, the number is negative. BN_dec2bn() is the same using the decimal system.

BN_print() and BN_print_fp() write the hexadecimal encoding of a, with a leading ’−’ for negative numbers, to the BIO or FILE fp.

BN_bn2mpi() and BN_mpi2bn() convert BIGNUM s from and to a format that consists of the number’s length in bytes represented as a 4−byte big-endian number, and the number itself in big-endian format, where the most significant bit signals a negative number (the representation of numbers with the MSB set is prefixed with null byte).

BN_bn2mpi() stores the representation of a at to, where to must be large enough to hold the result. The size can be determined by calling BN_bn2mpi(a, NULL ).

BN_mpi2bn() converts the len bytes long representation at s to a BIGNUM and stores it at ret, or in a newly allocated BIGNUM if ret is NULL .

RETURN VALUES

BN_bn2bin() returns the length of the big-endian number placed at to. BN_bin2bn() returns the BIGNUM , NULL on error.

BN_bn2hex() and BN_bn2dec() return a null-terminated string, or NULL on error. BN_hex2bn() and BN_dec2bn() return the number’s length in hexadecimal or decimal digits, and 0 on error.

BN_print_fp() and BN_print() return 1 on success, 0 on write errors.

BN_bn2mpi() returns the length of the representation. BN_mpi2bn() returns the BIGNUM , and NULL on error.